It also mounted a rocket attack on suspected militants on the Sinai peninsula, two months after a military takeover that deposed Mohammed Morsi, Egypt's first democratically elected president.

Court officials said one Brotherhood member was handed down a life sentence, 48 were given jail terms ranging from five to 10 years, and three to 15 years in prison for their role in attacks on soldiers in Suez on August 14, which saw some of the fiercest clashes in recent memory. Twelve defendants were acquitted.

The clampdown since the installation of the military-backed government has targeted a wide range of Islamist leaders, supporters and media channels.

Separately, Cairo administrative court ruled that al-Jazeera television's local station Mubasher Misr, one of the last remaining television channels with perceived Islamist sympathies, should be taken off-air.

The Egyptian arm of Qatar’s media empire has faced hostility since the change of government. Its offices have been repeatedly raided, with dozens of staff detained. Two remain in custody.

Government officials have accused it of operating without a permit and spreading rumours. The court ruled that four other channels should also be banned.

There were also reports that army helicopter gunships had killed eight and wounded 15 more in an attack on extremists in the Sinai Peninsula.

The largely lawless border with Gaza and Israel has seen an upsurge in Islamic terror activity in the two months since Mr Morsi's fall.

Regular attacks on security installations killed 25 policemen in the last month, reviving fears of an Islamist insurgency similar to that which ravaged the country's tourism industry during the 1990s.

Egyptian troops have stepped up their crackdown on the militants, arresting suspects, destroying smuggling tunnels to Gaza, and establishing a buffer-zone along the border. According to local residents, some 20 houses have been destroyed in the process.

Mohamed Ibrahim, the interior minister vowed this week to use a firm hand to ensure Sinai is a "terrorist-free zone" by the end of 2013. In a sign of the breakdown in public relations between Egypt and Gaza's Hamas Party leaders, Mr Ibrahim insisted that the Islamist organisation is channelling money to Sinai's militants.

Mr Morsi will now stand trial on charges of "incitement to murder and violence", relating to deadly clashes in December between his supporters and opponents outside the presidential palace.

Others facing trial include senior Brotherhood figures Mohamed el-Beltagi and leaders such as Essam el-Erian, deputy head of the Freedom and Justice Party, the Brotherhood political wing.

Although the Brotherhood remains a legal organisation, this may soon change. On Monday, a judicial panel set up by Egypt's military-backed interim government supported a legal challenge to the organisation's status as an NGO, recommending that it be dissolved.

The Brotherhood officially registered as an NGO in March, circumventing a 1954 court ruling that banned the organisation.

It had grown used to operating underground during the Mubarak-era, but will now struggle in an environment that is more hostile to Islamists than at any time in recent memory.